A comprehensive research on new DyCo2Mnx (x = 0.0–1.0) Laves phases

Abstract

DyCo2Mnx (x = 0.0, 0.2, 0.4, 0.6, and 1.0) compounds were synthesised and found to all be single-phase, isostructural to DyCo2 (MgCu2 Laves phase cubic structure (Fd-3 m) at room temperature). DyCo2Mn exhibits a huge coercivity field HC = 21,170 Oe at 5 K. The magnetic transition at Curie temperature TC, was observed as first order for DyCo2 but second order for the Mn doped compounds. Using Kouvel-Fisher plot, critical isotherm analysis and Arrott-Noaks plot techniques, a detailed critical exponents analysis was carried out on these transitions: critical exponents β ≈ 0.5, γ ≈ 1.0, and δ ≈ 3.0 were derived indicating that all the second-order transitions belong exhibit long-range magnetic interactions during the magnetic transitions. High-resolution synchrotron X-ray measurements confirm that there are crystal structure transformations sychronised with the magnetic transitions from paramagnetism to ferrimagnetism (PM-FM) at TC in the x = 0.0 and 0.2 cases with crystal structure changing from cubic (Fd-3 m) to tetragonal (I41/amd), However structures remain cubic (Fd-3 m) for x = 0.4, 0.6, and 1.0.